Wink gesture control system

ABSTRACT

A wink gesture based control technique for entering text, selecting, controlling and manipulating virtual objects and smart applications on a display using facial gestures of the user, in particular winking, blinking and squinting movements of the eyes. The wink gesture based control technique utilizes wink gestures of a user to select, control, and manipulate virtual objects on a display. A head mounted device is adapted to allow detection and classification of specific wink gestures. The head mounted device in some embodiments may also be adapted to recognize certain characteristics of the wink gestures, such as duration or amplitude, to allow enhanced navigation of a computer interface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/181,475 filed Nov. 6, 2018, which is a continuation in part of application Ser. No. 14/993,134, filed Jan. 12, 2016, which claims the benefit of U.S. Provisional Application No. 62/102,235, filed Jan. 12, 2015.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable to this application.

BACKGROUND Field

Example embodiments in general relate to a wink gesture based control system for entering text, selecting, controlling and manipulating virtual objects and smart applications on a head mounted display using wink gestures and/or facial expressions of the user.

Related Art

Any discussion of the related art throughout the specification should in no way be considered as an admission that such related art is widely known or forms part of common general knowledge in the field.

Digital devices are prevalent throughout the world. For example, mobile smart phones, smart glasses, smart watches, and the like are becoming more and more popular as their functionalities are improved. In some areas of the world, it is rare for an individual to leave the house without relying in some way on such a digital device. This is particularly true in a wide range of industries, where digital automation has resulted in numerous body-worn devices which may control other units from a remote location.

While such digital devices provide a range of functionalities, they typically suffer from the shortcoming that they require the use of hand (by touch or gesture) or speech inputs for operation. For example, smart phones typically include a touchscreen which is utilized to enter nearly all input instructions or to navigate a user interface. This can be particularly burdensome for those without full use of their hands, either due to medical issues such as disabilities or due to the nature of the work being performed. For example, a surgeon will often desire to utilize such a digital device, but would be limited if performing a task that requires both hands, such as surgery. Speech input has recently also gained popularity in controlling digital devices, however there are a host of real-world applications where both speech input and hand gesture input is impossible or undesirable, because the surrounding environment is either too noisy or requires secrecy, which by elimination only leaves input by wink gestures as a practical mode for controlling the user interface of such devices.

SUMMARY

This disclosure provides a method. The method includes entering text on a computer system using a regular expression based shorthand notation based on character placeholders in order to be able to achieve predictive text input with a minimum of input command operations. Possible input command operations comprise wink gestures. The method also includes a prediction step, whereby prediction of user-intended text is achieved by matching the tokenized regular expression input sequence against an n-gram language model.

There has thus been outlined, rather broadly, some of the features of the wink gesture based control technique in order that the detailed description thereof may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional features of the wink gesture based control technique that will be described hereinafter and that will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment of the wink gesture based control technique in detail, it is to be understood that the wink gesture based control technique is not limited in its application to the details of construction or to the arrangements of the components set forth in the following description or illustrated in the drawings. The wink gesture based control technique is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of the description and should not be regarded as limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments will become more fully understood from the detailed description given herein below and the accompanying drawings, wherein like elements are represented by like reference characters, which are given by way of illustration only and thus are not limitative of the example embodiments herein.

FIG. 1A is a first perspective view of a wink gesture based control system in accordance with an example embodiment.

FIG. 1B is a second perspective view of a wink gesture based control system in accordance with an example embodiment.

FIG. 2 is a block diagram of an example embodiment.

FIG. 3 is a frontal view illustrating parameters relevant for optical wink detection.

FIG. 4 illustrates electrode positioning for use in wink detection.

FIG. 5 is a frontal view of a rotating cylinder region of interest.

FIG. 6 is a frontal view of a scrolling region of interest.

FIG. 7 is a frontal view of both rotating and scrolling region of interests utilizing simulated magnetic attraction.

FIG. 8 is a graph illustrating the correlation between scrolling speed and wink amplitude in one embodiment of the present invention.

FIG. 9A is a first exemplary diagram illustrating potential wink input types.

FIG. 9B is a second exemplary diagram illustrating potential wink input types.

FIG. 10A is an illustration of a two-digit numeral input region of interest.

FIG. 10B is a flow chart illustrating two-digit numeral input via winks.

FIG. 11A is an illustration of a three-digit numeral input region of interest.

FIG. 11B is a flow chart illustrating three-digit numeral input via winks.

FIG. 12A is an illustration of a method for inputting alphanumeric character strings into a smart application hosted on a head mounted device by wink gestures.

FIG. 12B is a flowchart illustrating a method for inputting alphanumeric character strings into a smart application hosted on a head mounted device by wink gestures.

FIG. 13 is a flowchart illustrating a method for inputting text by wink gestures using a placeholder interpretation algorithm.

DETAILED DESCRIPTION A. Overview

FIGS. 1 through 12B illustrate an exemplary wink gesture based control system which generally comprises a head mounted device which utilizes wink gestures of a user to select, control, and manipulate virtual objects on a display. The head mounted device may have a display area within a user's field of view in which a user can view an overlay of both physical objects and virtual objects rendered via the display.

Sensors on the head mounted device are utilized to detect and interpret facial gestures or expressions of the user to navigate the region of interest of the display. Sensors may include cameras, electromyography sensors, distance sensors, motion sensors, electrooculography sensors and a variety of other sensors. The sensors may detect facial gestures such as winking, blinking or squinting. The head mounted device is adapted to allow manipulation of any user interface, or of virtual objects populating a head mounted display, in response to specific facial gestures (such as winks, blinks or squints). The head mounted device in some embodiments may also be adapted to recognize certain characteristics of the facial gestures, such as duration or amplitude, to allow enhanced navigation of the region of interest.

B. Device and System Architecture

The configuration, size, and type of head mounted device may vary widely in different embodiments of the present invention. By way of example and without limitation, the head mounted device could comprise goggles, glasses, a hat, a sweatband, or any other wearable device which may or may not include an integrated display.

FIGS. 1A and 1B illustrate an example of a wearable computing system representing a head mounted device 240 (HMD). The HMD 240 includes a face gesture detection system. While FIG. 1 illustrates a head-mountable device as an example of a wearable computing system, other types of wearable computing systems could be used. In particular it is optional to include an internal display with the wearable computing system. A display is required to operate the face gesture detection system; however both external and internal displays are equally suitable for operating the system.

The present invention is particularly suitable for manipulating virtual objects which are superimposed onto a user's field of view in an HMD 240. The wearable computing system consists of a frame 140 which comes into direct skin contact with the user's face around the nose and above the ears. Contact with the nose is established via the nose bridge and nose pads 121. The temple tips 140 are part of the frame and are used to both secure the HMD 240 to the head and to provide an optional placement site for additional surface electrodes.

Attached to the HMD 240 frame are a plurality of sensors whose purpose is to detect wink gestures. The sensors attempt to detect wink gestures by one or more of the following techniques: electromyography (EMG), electrooculography, facial distance sensors, facial motion sensors, visual gesture recognition by image processing. Other kinds of suitable techniques are not excluded. Both the electromyography and electrooculography methods require a plurality of electrode-based sensors 130. These sensors may comprise surface electrodes as opposed to needle electrodes.

The set of EMG electrode sensors may comprise both active electrodes and reference electrodes. A distance and/or motion sensor 110 may be attached to the frame in a position where the eye region can be observed. Of particular significance for distance sensors is the region just below the eye 115 where the Zygmaticus muscle groups flex and contract in response to a squinting gestures of the user. Various other muscle groups may be utilized, with the bulge of the muscle groups being detectable.

In order to implement gesture recognition by image processing a plurality of user-facing cameras 120 may be used. The purpose of these cameras 120 is to illuminate as much of the eye region 125 as possible, including eyebrows, nose bridge and eye sockets. The cameras 120 may either operate in the visual or infrared spectrum. If the infrared spectrum is used, then an infrared lighting system needs to be additionally attached to the HMD 240 in order to illuminate the observed facial regions.

FIG. 2 shows an exemplary architecture of a typical HMD 240 which may be enhanced with the described input methods by wink gestures. The exemplary HMD 240 depicted in FIG. 2 makes use of one or more processing units 205, a transceiver 210, a plurality of communications interfaces 215, utility sensor devices 229, data storage 239 and user input/output devices 270. The utility sensor devices 229 may consist of sensors such as orientation sensors 220, motion sensors 225 and a various other related sensors. The data storage module 239 stores both program logic 230 and program data 235. The user input/output devices consist of both generic HMD devices such as front-facing camera 261, display 262, speaker 263, microphone 264 or touchpad 265, as well as devices which are primarily dedicated to the recognition of wink gestures 259, namely rear-facing cameras 120 for face/eye gesture recognition 251, electrooculography sensors 253, electromyography sensors 254 and facial distance/motion sensors 255.

i. Visual Wink Gesture Detection System

FIGS. 1A and 1B depict an exemplary method and system for detecting winking and squinting gestures using an HMD 240 through use of a plurality of rear-facing cameras 120 operating either in the visual or infrared band. The rear-facing cameras 120 are used to map the relative positions of pre-defined reference points 330, 331 and 332 on the eye brow 321, upper 331 and lower 330 eye lids of both eyes 322. Other or additional reference points may also be defined.

FIG. 3 illustrates an exemplary method for detecting winking and squinting gestures through use of rear-facing cameras 120. For mapping purposes, lines 310, 311 and 312 are drawn between equivalent points on both sides of the face. The angles of these lines to the verticals 313, 314 are measured. It is these angles which can be used to estimate whether a wink gesture event has taken place, what side of the face the wink gesture event has occurred and what amplitude and duration the gesture event has exhibited. An alternative embodiment of this method would involve measuring the distances between the said reference points and use the ratios of these measurements from either side of the face to estimate whether a wink gesture event has taken place, what side of the face the gesture event has occurred and what amplitude and duration the wink gesture event has exhibited.

ii. Electromyographic Wink Gesture Detection System

FIG. 4 depicts a system for implementing a wink gesture detection system by using electromyography (EMG). EMG generally necessitates the use of either surface or needle electrodes. The electrodes 440, 441, 442, 443 and 444 are all surface electrodes, such as electrodes based on silver nanowires for example, though other types may be utilized. Silver nanowire sensors are as accurate as the wet electrode sensors used in hospitals but are more accurate when the user is moving and as such they are particularly suitable for use in a wink gesture detection system.

The EMG-based wink gesture recognition system generally requires at least one reference electrode and a plurality of signal electrodes. As shown in FIG. 4 , an exemplary embodiment has a first electrode 440 on a first side of the nose, a second electrode 441 on a second side of the nose, and a third electrode 443 on the bridge of the nose. As shown in the figures, the electrodes 440, 441 may be integrated with or connected to a nose pad 411. Electrode 442 may be integrated with or connected to a nose bridge 410.

Electrodes 442 and 444 would be particularly suitable for use as reference electrodes. Electrode 442 may be used as either a reference electrode or a signal electrode. If used as a signal electrode, electrode 442 is particularly suited for detecting a frowning-type facial gesture.

Electrodes 440 and 441 are the primary signal electrodes for wink detection. A wink is detected if a suitably normalized voltage differential is observed by a special processor which takes as input the voltages 432 measured through the signal electrodes, in reference to a ground 431. For better signal quality and in order to minimize the movement artifacts which are generated by the movement of the electrode with respect to the skin, both high-pass signal filtering and use of an active electrode is envisaged. An active electrode is a design whereby the input amplifier 450 is put on the electrode 440 and where the electrode has two or more connectors 451, 452 where direct skin contact is established. The connectors 451, 452 are in turn connected to an amplifier 450. This permits differential amplification to be used to ensure minimal distortion and the highest possible signal-to-noise ratio for the electrodes 440, 441, 442, 443, 444.

In one embodiment, two signal electrodes 440, 441 may be brought into contact with the user's skin on or near the temples on each side of the face. In some embodiments, at least four signal electrodes 440, 441, 442, 443 may be brought into contact with the user's skin, including areas on each temple and each side of the nose. The reference electrodes 440, 441, 442, 443 may contact above the ears or on the nose bridge, among other locations which exhibit minimal movement.

C. Controlling Smart Applications by Facial Gestures

One of the prime reasons for equipping an HMD 240 with the sensors described herein is to enable the control of smart applications hosted on an HMD 240 with an integrated display. When controlling a computer application of any kind, it is of central importance to be able to select items from lists and to be able to enter numeric or alphanumeric data. The present invention has put particular emphasis on providing methods which allow the control of a smart application either assisted by wink gestures, or by wink gestures alone. The aim was to determine the fastest and ergonomically optimal solution for interacting with an HMD-hosted smart application by means of wink gestures.

Probably one of the central problems for any user interface is how to display a list of items, iterate through that list on a display and let the user select a list item. A list may, for example, consist of menu items or a sequence of allowed input for a given input field.

FIG. 5 depicts a symbol wheel 520 which is a data entry paradigm of particular significance in the context of the present invention. A symbol wheel is a simulated wheel rotating around a central axis 521. Attached to the outside of the wheel are symbol cards 540. It needs to be emphasized that the purpose of the wheel paradigm is to allow the user to preview the next symbols before they reach the selector window 541. It is not necessary to simulate a physical wheel with mathematical precision. It is sufficient in the context of the invention that the moving object gives the user the general impression of a rotating wheel. The wheel is moved by applying simulated torque 510, 511 in either direction of spin. A symbol card is selected when the wheel comes to rest and a particular symbol card is visible in the selector window. The visible card then has the active focus 541.

FIG. 6 depicts an alternative embodiment of an HMD-capable list selector. This list selector is based on the paradigm of a moving scroll 530, 620. The main differences between the scroll and wheel paradigms are that a scroll is finite in either direction 610, 611, whereas a wheel can be spun indefinitely. Moreover a wheel can preview more symbols than a scroll since the simulated perspective makes symbols progressively smaller the nearer one gets to the top of the wheel.

A general problem with both scroll and wheel based list selection is the problem of how to ensure that only one symbol can come to rest in the selector window 530 when the moving object comes to rest. FIG. 7 shows how this problem can be solved with simulated magnetic attraction 710 when in analogy to a slot machine the wheel can only ever stop on a specific symbol card.

The present invention envisages that both wheels and scrolls are moved by applying simulated torqued which is in turn commanded by scalar inputs such as scalar-capable wink gestures, i.e. gestures which have either an amplitude or duration from which the amount of simulated torque can be derived. However, it should also be appreciated that binary inputs (parameterless events) or vector inputs (events which have parameters exhibiting both direction and magnitude) may also be utilized by the present invention.

FIG. 8 illustrates that an exponential relationship is suggested when translating the scalar value of the gesture control input into an equivalent amount of simulated torque. The scalar component of the control input may be a function (linear or exponential) of the amplitude of the wink gesture. The amplitude of such a wink gesture is determined by measuring the degree of facial distortion associated with the wink gesture.

FIGS. 9A and 9B specify the control inputs intended to be used with the present invention. It is emphasized that the control inputs specified in FIGS. 9A and 9B are not intended to be restrictive in the sense that they may be supplemented with further wink gestures or other control input not based on wink gestures.

FIG. 9A illustrates exemplary wink gestures which deliver a scalar value designating the magnitude of the control input. The scalar-capable control inputs are further differentiated into duration-based and amplitude-based inputs. The former comprise of the amplitude-dependent left wink 901 and the amplitude-dependent right wink 902. The latter comprise of the duration-dependent left wink 910, the duration-dependent double-sided wink 911 and the duration-dependent right wink 912.

FIG. 9B illustrates exemplary non-parametrized gestures, i.e., gestures which exhibit no intrinsic scalar value. These gestures comprise of the left single wink 920, the double-sided single wink 921, the right single wink 923, the left double-wink 930 and the right double-wink 931. It should be appreciated that the figures are not exhaustive as to types of wink gestures which can be recognized. For example, wink gestures that may be recognized may comprise, without limitation, a short single-sided single-squint; short single-sided double-squint; duration-based single-sided squint; duration-based double-sided squint; amplitude-based single-sided squint.

FIG. 10A shows an embodiment whereby the task is to select from two lists simultaneously. An example would be the input of a two digit number. To achieve this task with the minimum amount of control input, two symbol wheels are utilized, which are each populated with the full set of single digit numbers. Both symbol wheels can be spun in one direction only by applying simulated torque 1010, 1020 through a wink gesture. The wink gestures used in this embodiment are the amplitude-dependent left wink 901, which controls the left wheel 1040, and the amplitude-dependent right wink 902, which controls the right wheel 1030. The flow diagram of FIG. 10B further illustrates the described concept in that the start 1050 may consist of either spinning the left 1040 or the right wheel 1030. The wheels can be spun repeatedly in any sequence until the selection procedure is terminated 1053, 1054 by a double-sided single wink 921 which confirms the selection.

FIG. 11B represents a variation of the concept illustrated by FIG. 10 in that more than two symbol wheels are used to make numeric input. Once more than two symbol wheels are used it is no longer possible to associate a symbol wheel with a particular eye and a method 1130 is required to define an active wheel 1120 and to shift the active focus to a different wheel which was previously inactive 1110. It is only the active wheel which can be spun by simulated torque 1140 applied by means of an amplitude-dependent wink gesture. The flow diagram of FIG. 11B illustrates this concept. From the start 950 of the selection procedure the user can either skip the active focus to a different wheel 951 or spin the active wheel by means of an amplitude-dependent gesture 952. At the end 954 of the procedure the selection is confirmed 953 by a double-sided single wink 921.

FIG. 12A depicts another embodiment of the present invention whereby alphanumeric input is being entered by the exclusive means of wink gestures. This embodiment of the invention uses an input paradigm which is based on analogies with a classic mechanical typewriter featuring a moving carriage 1310. On the carriage there is a number of empty slots to take symbol cards. The number of empty slots 1341 is equal to the number of characters in the string which is to be input. There is one single active wheel 1320 which is fixed in position behind the moving carriage. The active symbol wheel may be substituted by a plurality of alternative symbol wheels 1330 or 1336. The command actions available when entering alphanumeric input are the following: substitute alternative symbol wheel 1331 or 1332, move carriage by one position (left or right) 1311, rotate wheel clockwise 1022, rotate wheel counter-clockwise 1021 and confirm input.

The flowchart of FIG. 12B illustrates the control flow of the described embodiment. Similar to the embodiments described previously the active symbol wheel may be spun by amplitude-dependent gestures 1352. What is different to the previous examples is that another symbol wheel may be substituted 1351. This may be achieved by performing either a left or right double-wink gesture. A left-wink gesture implies that the set of alternative symbol wheels is iterated towards the left, whereas a right-wink gesture implies an iteration towards the right. Left and right single-wink gestures are reserved to move the carriage by one position 1353. A left single-wink gesture implies moving the carriage one position to the left, whereas a right single-wink gesture implies moving the carriage by one position to the right. Similar to the previous embodiments, a double-sided single wink confirms the inputs and lets the user exit the input mode 1354, 1355.

D. Regions of Interest, Points of Interest and Augmented Reality Objects

Some embodiments allow for interacting with a head mounted display to select point-of-interest and augmented reality targets. When detecting a human wink gesture, the system can trigger a head mounted display to select a subset of the points or interests or augmented reality targets within the region of interest in the field of view. The regions of interest may be adjusted by wink gestures which have been detected and interpreted by the head mounted device.

The various embodiments include methods of selecting augmented reality targets, including defining a region of interest based on user's wink gestures by capturing spatial data with one or more head mounted sensors, displaying a shape outlining the region of interest on the display of the head mounted display, calculating parameters including distance with respect to the head mounted display that corresponds to the augmented reality targets, displaying a plurality of virtual objects within the region of interest, reducing the size of the region of interest based on the amplitude or duration of the user's face gesture input and using a reduced-sized region of interest to select a specific virtual object target.

A user may select a specific layer of region of interest or object target augmentation by first selecting the region of interest using face gesture inputs. In case multiple augmentations such as virtual objects are overlayed onto the selected augmented reality target, the user can iterate through them in the direction of the target using either amplitude-sensitive face gestures 901, 902 or duration-sensitive gestures 910, 912. The direction can be set on the basis of whether the winking movement occurs on the left or right side of the face. The speed of the iteration can be controlled by the amplitude or duration of the wink gesture.

According to another embodiment, the system can start, control and terminate head mounted display-based or mobile applications based on wink gestures. For example following a cue by wink gesture, a region of interest can be defined as an input area for an optical character recognition (OCR) translation system. Another wink gesture may be used to either terminate the smart application or to shut down the head mounted display itself.

According to another embodiment, the wink gestures can be utilized to narrow or widen the field of view (zooming) for video sharing or image/video capture depending on the side (left or right eye) and amplitude of the wink gesture. The wink gestures can be utilized to focus the field of view for video or still image capture; thus controlling the focus and/or field depth of the camera depending on the amplitude of the wink gesture. An example would be a frontal-facing head mounted display camera on which the user can manually adjust the focus by amplitude-dependent wink gestures.

According to another embodiment, the described wink gestures can be used to control smart applications on the head mounted display using the usability paradigm of a computer mouse. Analogous to a traditional computer mouse, with its left-clicks, right-clicks, single-clicks and double-clicks, there can be left-wink, right-wink, single-wink and double-wink gestures with the same semantics of the corresponding computer mouse operations as shown in the figures. This mode of operation is of particular significance when eye movements of the user are tracked (for example by sophisticated electrooculography-based methods) and translated into the movement of a mouse pointer in the field of view. Whenever the mouse pointer hovers over a surface suitable to be clicked on, the necessary click-action can be commanded using the described wink gesture inputs.

In another embodiment, real-world text (such as signage) may be captured within the region of interest by wink gestures. A second facial gesture may then be utilized to initiate a translation based on the captured text, which is displayed to the user via the head mounted display. For example, a first set of wink gestures may be provided to capture the text within the region of interest, and a second wink gesture may be provided to initiate the translation. Other wink gestures may be utilized to enlarge, reduce, or move the region of interest to capture more or less text. Additional wink gestures may be utilized to perform a visual recognition search within the region of interest or to disengage the region of interest.

E. Entering Text by Facial Gestures

When entering text by facial gestures predictive text input is advantageous because of the difficulties to efficiently select letters from a virtual keyboard by facial gestures. The prior art primarily employs prefix based predictive text input algorithms. Prefix based predictive text entry is partially suitable for languages such as English where the average word length is approximately 5 characters. Other languages have longer mean word lengths as words are combined into longer compound words and prefix approaches are thus less effective.

An embodiment of the present invention utilizes a placeholder interpretation algorithm which is a variation of an abbreviation expansion algorithm. In a placeholder interpretation algorithm the user enters text by mentally deciding which are the significant characters in each word and in each phrase, the user then skips the non-significant characters by replacing them with placeholders. Using a statistical language model with n-grams, such as bigrams or trigrams in a preferred embodiment, are matched against n-grams in the input text. The input text comprises an indication of the length of each word plus any number of significant characters. If the user-intended text were “Mary had a little lamb” for example, then the user could input said text as a data-compressed input pattern such as “Mary ##d ####tle ##mb” or “Mary ##d #l###le l##b”, or any other permutation which would appear intuitive to the user, wherein the # character represents a character placeholder. User training is essential to achieve good results with this method. The user needs to develop an intuitive feel of how many placeholders and what kinds of significant characters are allowable in order to yield good prediction results whilst at the same time aiming to reduce the amount of user inputs to a minimum. A good guide would be that the intended text could be guessed without excessive effort by another human reader.

From a conceptual point of view, one may regard a character placeholder as analogous to the word character “\w” in regular expression syntax. Regular expressions are patterns used to match character combinations in strings. Regular expression patterns are composed of a sequence of atoms. An atom is a single point within the regular expression pattern which it tries to match to the target string. Therefore a placeholder interpretation algorithm, such as the one introduced in this specification, is essentially a way of allowing a user to enter text as simple regular expressions patterns which are in a later step tokenized and transposed into n-grams, whereby the n-grams are then, in turn, matched against the n-grams of a language model in order to derive a prediction. In a preferred embodiment predictions are derived by using trigrams.

In a preferred embodiment the input pattern is tokenized into input tokens, wherein an input token is defined as a sequence of character placeholders and/or alphanumeric characters followed by a word-separating symbol or a sentence-separating symbol. After the tokenizing step the sequence of input tokens is transposed into n-grams. The n-grams derived from the input tokens are regular expression patterns which can then matched onto the n-grams of an n-gram language model.

The described text entry method can also be understood to involve using a form of data compression in order to reduce the number and complexity of user operations, i.e. wink gestures, which are required for entering a text. When the input sequence of symbols is reconstituted to clear text, this can be seen as analogous to uncompressing the data-compressed format. In the prior art data compression techniques are usually applied to storing or transmitting data more efficiently. In the context of the present invention, however, an innovative form of data compression is employed at the point of user input instead. The utilized form of data compression cannot be considered lossless since the user may be required to manually correct ambiguous decompression results. In a preferred embodiment this step of manual correction is achieved by presenting the user with lists of alternative decompression results and the user is then required to select the correct interpretation out of the list of possibilities.

An n-gram language model models sequences, pertaining to strings of natural language, using the statistical properties of n-grams. An n-gram model predicts X_(i) based on X_(i-(n-1)), . . . , X_(i-1). In probability terms, this is P(X_(i)|X_(i-(n-1)), . . . , X_(i-1)). When used for language modeling, independence assumptions are made so that each word depends only on the last n−1 words. This Markov model is used as an approximation of the true underlying language.

The flowchart of FIG. 13 describes an embodiment wherein text is entered by wink gestures and by using the innovative placeholder interpretation algorithm. After the start event 1400 the user may enter either a character placeholder 1401, or an alphanumeric character 1402. A character placeholder may substitute any alphanumeric character. In a preferred embodiment a character placeholder is entered by a right-sided single wink gesture. Multiple character placeholders may be entered in one single operation by a duration-dependent right-sided wink, whereby the number of inserted character placeholders is a function of the duration of the wink gesture. In a preferred embodiment a left single wink gesture commands the system into alphanumeric character entry mode. In said mode a character may be selected from a spinning alphabet wheel analogous to the rotating active symbol wheel of 1320 of FIG. 12A. In a preferred embodiment a right-sided single wink gesture selects a character from the wheel, when in alphanumeric character entry mode. Any character placeholder and any alphanumeric character may be followed by either a word-separating symbol or a sentence-separating symbol. In a preferred embodiment a word-separating symbol, which is analogous to the space bar on a typewriter, may be entered by executing a double-sided single wink gesture. Likewise, a generic sentence-separating symbol, analogous to a period character, may be entered by executing a left-sided single wink gesture. Depending on available processor power a text prediction step 1404 may be executed after each symbol-entry operation, i.e. 1401, 1402 or 1403. In a preferred embodiment the text prediction step is executed after each sentence-separating symbol is entered. The text prediction step may match n-grams of the entered text against an n-gram language model. The system may then present to the user a prediction screen, where the predictions are shown in a list ordered by a score. The user may then select a prediction from the list, which is then transposed onto the input string. Transposition means in this context that the character placeholders of the input string are being replaced by the corresponding alphanumeric characters of the selected list entry. Should no list entry match the intent of the user, then the system may switch back to text entry mode. The user may then opt to replace arbitrary character placeholders by alphanumeric characters and then re-run the text prediction step. This action may be repeated until such time that the user determines that the predicted text fully matches the user's intent.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar to or equivalent to those described herein can be used in the practice or testing of the wink gesture based control system, suitable methods and materials are described above. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety to the extent allowed by applicable law and regulations. The wink gesture based control technique may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive. Any headings utilized within the description are for convenience only and have no legal or limiting effect. 

The invention claimed is:
 1. An electronic device comprising: a head-wearable frame comprising: a nose bridge; and one or more nose pads; and a right temple tip; and a left temple tip, wherein, when the head-wearable frame is worn on a head of a user, the frame is configured such that: the nose bridge is positioned atop the user's nose and in front of at least one eye of the user's head, and the right temple tip is held against a right surface of the user's head, and the left temple tip is held against a left surface of the user's head; and a plurality of light-emitting components, operative to emit light, wherein said light comprises the infrared spectrum and wherein said light-emitting components are configured to illuminate a part of the user's face; and a first sensor assembly attached to a part on the left side of the frame, wherein said first sensor assembly is configured for sensing an eye gesture made on a left side of said user's face, and a second sensor assembly attached to a part on the right side of the frame, wherein said second sensor assembly is configured for sensing an eye gesture made on a right side of said user's face; and a processor operative to: analyze sensor data from said first sensor assembly and said second sensor assembly; and determine an eye gesture of the user based on the analyzed data and wherein said eye gesture is parametrized with a duration and an amplitude.
 2. The electronic device of claim 1 wherein at least one of said sensor assemblies comprises a sensor, wherein said sensor is attached to the frame at a location where there is skin contact when the head-wearable frame is worn on a head of a user, and wherein said sensor is capable of detecting at least one contraction of at least one facial muscle.
 3. The electronic device of claim 1, wherein the processor is further operative to make an input through a user interface of the head-wearable electronic device, wherein said input is based on the determined eye gesture.
 4. The electronic device of claim 3, wherein the determined eye gesture requires a minimum duration before said input is made.
 5. The electronic device of claim 3, wherein said input is a scalar function of an amplitude of said gesture.
 6. The electronic device of claim 5 wherein said action is parametrized with a scalar value and wherein said scalar value is correlated to a duration of an eye gesture.
 7. The electronic device of claim 5, wherein said action comprises a scrolling function and wherein a scrolling speed of said scrolling function is correlated to said scalar value.
 8. The electronic device of claim 7, wherein said degree of distortion is correlated to a bulge on the user's face and wherein said bulge is of a type which is caused by a contracting facial muscle.
 9. The electronic device of claim 5, wherein said amplitude is correlated to a degree of facial distortion.
 10. The electronic device of claim 5, wherein the first muscle bulge sensor assembly comprises a distance sensor, wherein said distance sensor is configured to enable a time-series of measurements of a distance between said sensor and a facial surface, wherein said facial surface is located atop a muscle group.
 11. The electronic device of claim 1, further comprising: a display capable of overlaying virtual objects and real-word objects, and an eye tracking assembly for determining a gaze direction of the user, and a processor, operative to perform an action in response to the eye gesture having been determined, wherein said action is conditional on a gaze direction of the user having been directed towards an actionable object, wherein said action is parametrized with a scalar value and wherein said scalar value is correlated to an amplitude of an eye gesture.
 12. The first sensor assembly of claim 1, wherein said first sensor assembly is configured for sensing a distance to a reference point on the user's face.
 13. A computer-implemented method for translating combinations of user gaze direction and predetermined eye gestures into user input instructions for a head mountable computing device, the method comprising: causing at least one processor of the device to render a user interface, wherein the user interface comprises an element that is selectable for performing a command input; receiving, from at least one sensor of the device, eye tracking data that is indicative of a gaze direction of a user of the device; monitoring the eye tracking data to determine when the gaze direction of the user is directed toward said element; identifying when the user performs a predetermined eye gesture while the gaze direction of the user is directed toward the element; and in response to the user performing the predetermined eye gesture, causing said user interface to process a command input.
 14. The computer-implemented method of claim 13, wherein the predetermined eye gesture is defined as an occurrence of two blinks or winks or squints of a predetermined eye of the user within a threshold period of time.
 15. The computer-implemented method of claim 13, wherein the predetermined eye gesture is defined as a predetermined number of blinks or winks or squints of a predetermined eye occurring within a threshold period of time.
 16. The computer-implemented method of claim 13, wherein the predetermined eye gesture comprises an indication of magnitude and where the indication of magnitude is derived from measuring a degree of facial distortion, wherein said distortion is associated with said gesture and wherein said command input is parametrized in such a way that it comprises said magnitude.
 17. The computer-implemented method of claim 13, wherein the predetermined eye gesture comprises an indication of direction and wherein the indication of direction is derived from the side of a face on which said gesture is made and wherein said command input is parametrized in such a way that it comprises said direction.
 18. The computer-implemented method of claim 13, wherein the predetermined eye gesture comprises an indication of magnitude and wherein the indication of magnitude is derived from measuring a duration of said gesture and wherein said command input is parametrized in such a way that it comprises said magnitude. 